This invention relates to improvement in and relating to a tool.
In particular, the tool is a cutting tool. A portion of the cutting edge of the blade of the tool is presented for cutting only when a portion of the frame of the tool is displaced on contact with an object to be cut, such that only sufficient blade as required is exposed. When the cutting action has been completed, the guide or frame of the tool returns to a position whereby the cutting edge of the blade is no longer exposed.
It is envisaged the tool will have the most practical use for precise woodworking procedures in the form of an improved hacksaw tool, and so forth.
However, the invention may have applications outside this field.
A number of cutting tools, in the form of saws are available in the prior art. In a typical hacksaw or keyhole saw the-frame runs substantially parallel to the line of a narrow blade. Typically, the blade of such tools is replaced as the teeth of the blade become blunt through use, or the blade is broken. The keyhole saw is particularly useful for fret work, hobby or craft work where precise cuts are required. The bigger version of such a tool (being the standard hacksaw) is more bulky, but is typically used for a range of cutting procedures.
The advantage of a hacksaw or a keyhole saw is that the blade is replaceable when it becomes blunt or broken. This is an advantage over saws with fixed blades that when blunt require sharpening, or if they get bent or structurally damaged, the saw typically has to be thrown away.
Whilst the advantage of the hacksaw is its versatility, and the ability to replace the blades, it is nevertheless a cumbersome tool. Typically the frame supporting the blade can get in the way. Further, the whole blade is exposed generally, and in use is fully available for use in cutting. However, it becomes correspondingly easier to cut too deeply into a surface where fine control may be required or the cut may be wider than required. The same or similar problems are inherent in any tool, including awls or drills, where the depth of a hole being punched/drilled and such like can be difficult to control.
Therefore, it would be an advantage to have a tool that:
a) incorporated a replaceable portion such as a blade or an awl-like portion and so forth depending on the tool, and
b) had the added feature of a guard which covered the cutting edge of the blade or the sharp end of the awl and so forth until the tool is used, and
c) the guard only exposed so much of the blade/awl as required for a particular function thereby enabling greater control of the cutting action, minimising the likelihood of the cut/hole made being too deep (or where relevant, too wide); and
d) the guard would not encroach on the work area and hinder the action of the saw/awl and so forth when in use; and
e) the tool would be easy to use, easy to repair and easy to replace blades/tool shafts and so forth.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
According to one aspect of the present invention there is provided a tool, the tool including a body capable of supporting a blade portion, the body also capable of receiving one end of a substantially elongate protecting apparatus, the protecting apparatus being adapted at its forward distal end to contact a portion of the surface to be cut by the blade portion, the protecting apparatus also including alignment means to maintain alignment of the blade portion relative to the surface being cut, the tool also including resilience means to facilitate displacement of the protecting apparatus relative to the position of the blade portion when in use, and the body also including a handle.
According to another aspect of the present invention there is provided a tool substantially as described above wherein displacement of the protecting apparatus relative to the blade portion is effected in conjunction with resilience means via forward pressure applied to the tool by the user resulting in the abutting means contacting a surface to be cut being pushed rearwardly to expose the cutting edge of the blade portion.
According to another aspect of the present invention there is provided a tool substantially as described above wherein the resilience means is attached at one end to a portion of the body, and at the other end towards the rearward end of the protecting apparatus.
Accordingly to another aspect of the present invention there is provided a tool substantially as described above wherein the blade portion includes any one of a standard saw blade and an awl capable of being used with the tool and replaced when damaged or worn, said saw blade including at least one of a hacksaw blade, drag saw blade, or cross-cut saw blade.
According to another aspect of the present invention there is provided a tool substantially as described above wherein the protecting apparatus includes gauging apparatus capable of being pre-set prior to use of the tool to ensure the cut effected by the blade portion does not exceed that required.
The term blade portion shall mean, but is not limited to any portion of a tool capable of effecting the required change in a surface with which the tool is used. For example, the blade portion may be a saw blade to effect a cut, or an awl shaft or drill bit to effect a hole, and so forth. However, the blade portion may also be or include a measurement scale, and so forth.
For ease of reference one embodiment of the tool in the form of a cutting tool incorporating a saw blade, shall now be described. However, it should be appreciated that reference to a cutting tool or a saw blade is not intended to limit this specification. Accordingly, the description may be generally applicable to a hole-punch tool where the blade portion is an awl, or any other such tool to which the features of this invention may be applied.
In preferred embodiments of the present invention the handle portion of the body is displaced at one distal end of the tool and is oriented in a plane substantially perpendicular to the plane of orientation of the blade portion and the protecting apparatus. Preferably the handle is moulded to enable it to be comfortably gripped within the user""s palm. Preferably, the contoured handle portion can be adapted so that it can be gripped comfortably by both left-handed and/or right-handed people.
Anterior to the handle the main portion of the body is configured to receive the protecting apparatus, the resilience means and the blade portion. There is also provision to receive a cover plate that can be removed as required to repair to and/or replacement of the resilience means and/or the blade portion and/or the protecting apparatus when these become broken or worn. Alternatively, the handle portion may pivot open to enable access to its interior to enable repair to and/or replacement of the resilience means and/or the blade portion and/or the protecting apparatus as required.
A transverse groove is preferably cut into the interior face of the main upper body portion to enable the substantially elongate protecting apparatus to slide within the groove in a substantially horizontal plane.
The groove preferably transverses the width of the body to ensure unhindered sliding movement of the protecting apparatus. Above the slide groove is located attachment points to which one end of resilience means, such as a spring, is capable of being attached. An attached resilience means, such as a spring or any other suitable resilience means, is thus configured to preferably lie in a substantially parallel plane to the plane of alignment of the protecting apparatus. Although any suitable attachment site for one end of the resilience mans, may be utilised as required.
Whilst one end of the resilience means (spring) is attached to the body, the opposite distal end of the spring is preferably attached to an attachment point (or lug). The lug is preferably positioned at the rearward distal end of the protecting apparatus (that in use is capable of sliding through and extending beyond the rear of the body).
In other preferred embodiments, the opposite distal end of the spring is preferably attached to an attachment point preferably positioned at a point within the handle, so that the attachment point on the protecting apparatus is substantially hidden from view.
Preferably adjacent (or above) the position of the resilience means the body is configured to receive a portion of a blade. Again the blade is preferably aligned in a substantially parallel arrangement to the protecting apparatus and the resilience means.
Where the blade is a saw blade its position, although displaced in distance from the protecting apparatus and the resilience means, is such that when the blade is assembled onto the body the teeth of the blade are oriented downwards towards the protecting apparatus.
The blade is preferably inserted in to a suitably configured cavity in the body. The blade is further maintained in the cavity by securing means in the form of a screw threaded lug, or bolt which can be turned to apply pressure to part of the blade.
The securing means is preferably located on the upper exterior surface of the body and is able to co-operate with the blade via a channel through the upper body, through which a shaft of the securing means can pass. In one embodiment the means for securing the blade into a preferred position also contributes to securing a cover plate of the tool in place.
However, any suitable arrangement and location of such securing means for securing the blade in place, may be employed with this invention. For example, the securing means may be located on the upper, but external surface of the handle/body and enables the blade to be secured into a preferred position whilst contributing to securing one half (or portion) of the handle/body of the tool in place relative to the remainder of the handle.
Once assembled the protecting apparatus, resilience means, and blade are maintained in their appropriate position by a cover plate removably attached to the body. Alternatively, the handle may be in two halves longitudinally. Positioning and securing one half to the other in such embodiments ensures that when the handle is assembled the protecting apparatus, resilience means, and blade are maintained in their appropriate position.
Preferably the cover plate (or portion or half of the handle/body) is suitably configured to complement the corresponding configuration of the body and the protecting apparatus, the resilience means and the blade to maintain them in their preferred locations.
An advantage of the cover plate of the present invention is that it can be easily removed to replace any worn springs, to lubricate the protecting apparatus to facilitate its sliding in the slide groove of the body, and to facilitate replacement of damaged or worn blades.
In one preferred embodiment, the cover plate may be totally detachable from the tool when required by undoing appropriate attachment means, such as screws, spring clips and so forth, and or the securing means of the blade.
In other embodiments the cover plate may remain attached to the body by hinging means, so that when the attachment means are undone or released, the cover plate is simply pivoted to expose the interior face of the body. Any combination of removable plates and hinged portions of the body/handle, in part or in its entirety, may also be employed.
In preferred embodiments of the present invention the protecting apparatus is a substantially elongate member extending in a substantially perpendicular plane to the body of the tool. The member is preferably substantially uniform in dimension along its length. The length of the member is determined by the length of the blade of the tool. The length preferably is such that none of the cutting edge of the blade is exposed when the tool is not in use.
Extending in a substantially vertical plane from the upper surface of the rearward distal end of the member is a projection or lug. It is to this projection that the rearward distal end of the resilience means is attached. However, in other embodiments, the projection may extend from either side or furthermost end face of the member. Alternatively, as discussed above, the lug or point of attachment of the spring to the protective apparatus may be substantially hidden within the body/handle portion of the tool.
The lug may be permanently affixed to the elongate member, or may be removable to enable the elongate member of the protecting apparatus to be slid out of and into the groove of the body for maintenance, without having to remove the cover plate.
Whilst the rearward distal end of the member co-operates with and slides within the groove of the body of the tool, the forward distal end is configured to include a alignment means in the form of a blade guide and an optional abutment means.
Both the blade guide and the abutment means extend from the member in a substantially perpendicular plane. The blade guide projects substantially above the member of the protecting apparatus, whilst the abutment means substantially depends from the member of the protecting apparatus.
The abutment means and the blade guide are preferably positioned at the most forward end of the member. However, in other embodiments the blade guide may be positioned posteriorly to the point of attachment of the abutment means.
The blade guide is preferably configured to include a vertical face, at the top of which is a substantially U-shaped portion. The U-shaped cavity created is capable of enclosing at least a portion of the body of the blade therein, but does not grip the blade. Rather, the blade guide preferably ensures the blade cannot move laterally to the line of cutting action. Accordingly, the likelihood of the blade breaking is reduced, and the maintenance of the blade in preferred alignment to effect a cut is achieved.
The abutment means includes a portion, the face of which abuts at least a portion of the surface of the object being cut. This abutting face provides a means of further supporting the tool relative to the surface of the structure during the cutting action.
The abutting face also enables a more substantially equal force to be applied to effect sliding of the protecting apparatus rearwardly towards the body of the tool thereby exposing only the preferred amount of the blade""s cutting edge needed to effect the cut required in the surface of the object being cut.
The abutting face can take any appropriate shape and can be removably attached to the abutment means. For example, when the object to be cut is circular, such as a pipe, only a portion of the circumference of the pipe may contact a flat abutting face. Therefore, an appropriately configured abutting face is preferably used to extend the point of contact of the abutment means with the object.
In preferred embodiments of the present invention the elongate member of the protecting apparatus also includes multiple apertures distributed along its length. The multiple apertures are capable of receiving a stop. The stop can take any appropriate shape to effect the required function. The positioning of the stop along the length of the member effectively operates as a depth gauge thereby preventing the protecting apparatus from sliding too far through the body and exposing too much of the cutting edge or shaft of the blade.
Accordingly, by appropriately positioning the stop along the member of the protecting apparatus the width (or depth depending on the blade and the tool) of the cut into the surface can be controlled, without having to rely on the individual user""s judgement alone. Greater control of the cut is thereby effected. The stop may be attached to the elongate member either anterior to or posterior to the handle.
It is preferable that the blade guide, the abutment means and the elongate member of the protecting apparatus may be made of metal for durability and strength. However, other materials such as plastics materials, fibre glass and so forth may be employed.
The blade is typically metal, although the cutting edge may hardened chrome, tungsten coated, diamond edged or so forth to improve the ability of the tool to cut into a particular surface. As mentioned previously, in one embodiment of the invention, the cutting tool is adapted to receive standard hacksaw blades, drag saw blades and crosscut saw blades. However, the blades or other cutting apparatus may be specifically configured for this tool.
The body, including the cover plate and handle portion may be made of plastics materials (including reinforced plastics materials), fibre glass, metal, wood and so forth, as can the stop. However, as can be appreciated the various parts of the cutting tool can be made of any material suited to its required use.
Whilst the invention is preferably applied to a hand held, manually controlled tool, the invention may be adapted to include or be connectable to a power source. The latter embodiment may be particularly relevant where a drill bit is used as the blade portion.